Enhancing nano indentation properties of Al 7075 alloy: The role of silver addition

• Novelty of the Study: Al 7075 alloy was not studied earlier by adding Silver (Ag) in various compositions for aerospace applications. • Importance of Silver Addition: Silver is harder than Al 7075, hence this will improvise the mechanical properties of the composite material. • Aim of the Research: This paper presents the experimental and analytical approach toward finding the right proportion of Silver in Al 7075 for aerospace applications. • Methodology: Al 7075 and Silver were melted with uniform mixing and prepared as samples. These samples were subjected to nanoindentation testing to examine the mechanical properties. • Potential Impact: The research findings are going to result in optimized material properties for the aerospace components when the ratio of Al 7075-Ag composite is optimised. Al 7075, valued for wide applicability in aerospace structures, remains prone to environmental degradation in harsh environments. Alloying can improve its hardness and elastic modulus. Unlike traditional reinforcements, silver (Ag) offers inherent hardness and resilience against environmental conditions. Additionally, it refines the microstructures to reduce pits and stress corrosion cracking. Therefore, this research employs experimental and numerical procedures to investigate the effects of Ag addition on the nanoindentation properties of Al 7075. The hardness and elastic modulus of Al 7075 with 1 %, 2 %, 3 %, and 4 % Ag by weight are measured through nanoindentation tests using a Berkovich indenter. Results show that 1 %, 2 %, and 4 % Ag additions enhanced hardness and elastic modulus, with the maximum values recorded for 4 % Ag. The 3 % Ag sample, though, had an unexpected reduction in hardness and modulus attributed to Statistically Stored Dislocations (SSDs) and Geometrically Necessary Dislocations (GNDs). Analysis of indenter depth and pile-up through the scanning probe microscope (SPM) and X-ray Diffraction (XRD) revealed that the specimen with 1 % and 4 % Ag by weight exhibit the highest and lowest values of deformation respectively. The experimental results are validated numerically and a good conformity is observed. Results indicate that Ag addition improves the mechanical properties of Al 7075, and makes it is a potential material for aerospace and high-stress applications.